What is best workflow for mfg a complex hierarchical product?

Hi, I was hoping to hear what workflow works for you in the real world. I am exploring the workflow that a small manufacturer might follow to manufacture and sell a high-tech product. For the purpose of the investigation, the product is a crystal radio with a multi-level BOM intentionally structured with typical corner cases.

From top to bottom, there are four levels in the BOM:

  1. Marketing Assy - what gets shipped to the customer (assume direct sales of qty 1). The marketing BOM includes the radio, a users’ manual, some accessories, and a nice box.

  2. Product Assy - the crystal radio product itself. The product BOM includes an printed circuit assembly (populated PCB), chassis electrical connectors, hookup wire, and the enclosure itself (which was sent to a paint shop that painting and stenciling was sub-contracted to),

  3. Printed Circuit Board Assembly (PCBA). The PCBA BOM is a bare PCB plus all the parts that go on it. Assembly is sub-contracted to a local contract manufacturer (CM), and the parts kit is consigned to the CM (or suitable process in ERPNext).

  4. Custom Part. One of the child parts of the PCBA is a custom inductor (aka a coil of wire). The BOM for the inductor includes a ferrite rod, some number of meters of wire, and a couple cm of heatshrink tubing. The coil is manufactured internally by the SMB, and included in the parts kit consigned to the PCBA CM.

I started by creating a Material Request to manufacture qty 10 of the marketing assembly for sending to beta testers. I only specified the marketing assy pn in the Material Request (aka Manufacturing Request) and did not import the parts from the marketing assy BOM into the request. I then created a Work Order from the Manufacturing Request. I also did not create a Production Plan.

What is my next step from here? Did I miss any steps? Can I somehow automatically issue POs for all raw material? Does the process trigger creating a PO to the CM to assemble the boards, or is it my job to stay aware and create a PO manually? Can a manufacturing order to build 10 custom coils be created automatically, or will it have to be created manually?

Sorry for asking such a “big” question. If anyone has created resources or knows of any, I would really appreciate references. Fwiw, https://discuss.frappe.io/t/purchase-order-based-on-production-order/ has some good direction but still just hints for me.